China has achieved a major engineering milestone by completing the world’s widest underwater tunnel — the Shiziyang Tunnel — in just 110 days. Located beneath the Pearl River in Guangdong province, this tunnel marks a new benchmark in infrastructure development, showcasing the country’s ability to execute large-scale projects at an unprecedented pace.
Stretching approximately 2.5 kilometers and boasting a width of 38.8 meters, the Shiziyang Tunnel is now the widest underwater rail tunnel ever constructed. It is a crucial component of the high-speed rail route connecting Guangzhou and Shenzhen — two of China’s most important economic hubs within the Greater Bay Area.
The tunnel was built using advanced boring equipment and modern digital systems, allowing engineers to work efficiently under challenging underwater conditions. A state-of-the-art slurry shield tunnel boring machine played a vital role in boring through riverbed sediments with minimal disruption, enabling the project to progress at an exceptional speed.
The construction was overseen by China Railway Group Limited (CREC), a major player in the country’s infrastructure sector. CREC integrated real-time monitoring, digital modeling, and automated segment installation to maintain quality and safety while meeting an extremely tight timeline. Despite being located under a major waterway, the entire tunnel was completed in under four months — a feat rarely seen in global construction.
Once operational, the Shiziyang Tunnel will serve as a high-speed rail passage designed for trains traveling up to 350 kilometers per hour. This will significantly reduce travel time between Guangzhou and Shenzhen and help improve traffic efficiency throughout the Greater Bay Area.
This project is part of China’s larger vision to strengthen regional transport networks and promote economic integration. The Greater Bay Area initiative, which includes Hong Kong and Macau along with mainland cities, aims to create a world-class economic region powered by smart infrastructure and rapid transit systems.
Beyond transportation benefits, the successful execution of the Shiziyang Tunnel positions China as a leader in underwater construction and fast-track engineering. Experts note that such projects reflect not only technological advancement but also strategic planning and resource mobilization on a national scale.
